Automatic mailing machines typically include imprinting systems, such as a postage meter, where the information imprinted on the envelope or other sheet-like median is attributable to a variable parameter of the median, such as imprinting a postage value indicia on an envelope wherein the postage value is based on the weight of the envelope.
In the mail processing field, it is desirable for a system operator to be able to deliver to mail processing equipment a batch of "mixed mail," that is, the batch is comprised of a large number of envelopes of varying dimensions, and variable thickness or weight. The ability of a mail processing system to process a large variety of mixed mail eliminates the need of the system operator from performing a preliminary step of presorting the mail. It is further desirable for mail processing equipment to be able to weigh the individual envelopes and affix the appropriate postage value indicia in accordance with the envelope weight. It is generally considered advantageous if the mail processing equipment can imprint a quality indicia upon envelopes varying in thickness from that of a postcard to approximately three-quarters (3/4) of an inch.
It is known a provide mail processing equipment comprised of a feeder for singularly delivering envelope in series to a transport assembly. The transport assembly deposits the envelope on a scale for weighing. After a sufficient time to assure a true scale reading of the envelope weight, commonly referred to as "weigh on the pause," the transport assembly again assumes control over the envelope and delivers the envelope to a so-called mailing machine. Such a mailing machine is most commonly comprised of an integral transport assembly and attached rotary print drum type postage meter. The mailing machine transport assembly assumes speed control over the envelope performing any necessary speed adjustments to the envelope required to match the envelopes traversing speed with the imprinting speed to the postage meter print drum to promote a quality indicia print. It is known for the postage meter to include a value setting mechanism and to adjust the postage meter printing mechanism for printing of the appropriate postage rate on the approaching envelope according to the envelope weight as determined by the scale. Reference is made to commonly-assigned U.S. Pat. No. 3,877,531 which describes in greater detail a prior art automatic mail handling machine.
It is desirable to provide a mail processing system as depicted above with (i) the capability to process a dimensionally wide variety of envelopes including thickness or weight, (ii) to do it as fast as possible in terms of envelope per second, (iii) while applying a quality postage indicia. The known mail processing systems has several limiting factors with respect to increasing throughput relative to system cost. One such limiting factor is represented by the time required in transporting the envelopes from one process station to another. Another limiting factor is reflected in the time necessary to obtain an accurate weight from the scale. While such factors as transport time and weighing time can conceivably be decreased by incorporating advanced system techniques, the rule of diminishing returns predicts that small improvements in system throughput by such an incorporation would be achievable at disproportional increases in system costs.
One possible alternative means of increasing the throughput of such mail processing systems is to provide multiple scales and a suitable transport system such that the scales are placed in alternate use. Such an arrangement would conceivably allow overlapping of system process or function to achieve a significant increase system through. However, such an alternative represents added cost from both an equipment and system complexity standpoint.